Changes in hormonal profiles during competition preparation in physique athletes.
Level 3 - non-randomized controlled study
Prospective non-randomized controlled cohort study comparing competing physique athletes against non-dieting controls.
PubMed 39261323 · doi:10.1007/s00421-024-05606-z
What was done
This prospective controlled cohort study evaluated endocrine and physiological changes across a competition cycle in 23 competing physique athletes (10 female, 13 male) compared to 20 non-dieting control athletes (10 female, 10 male). Competing athletes were assessed 23 weeks before competition (PRE), 1 week before (MID), and 23 weeks post-competition (POST), while controls were evaluated at similar intervals. Measures included energy availability (EA), body composition via DXA, muscle cross-sectional area via ultrasound, muscle strength, mood states, and serum hormone concentrations (ACTH, cortisol, estradiol, FSH, IGF-1, IGFBP-3, insulin, free/total testosterone, and SHBG).
What was found
The abstract reports statistical significance without providing absolute baseline or endpoint values. During preparation, competing athletes of both sexes experienced significant decreases in EA (p < 0.001), IGF-1 (p < 0.001), IGFBP-3 (p < 0.01), and absolute muscle strength (p < 0.01 to 0.001), with IGF-1 reductions associating with greater fat-free mass loss. Competing males showed significant decreases in total testosterone (p < 0.01), free testosterone (p < 0.05), and insulin (p < 0.001), along with significant increases in SHBG (p < 0.001), cortisol (p < 0.05), and fatigue (p < 0.05). All observed endocrine, strength, and mood alterations returned to baseline levels following the 23-week post-competition recovery period.
Why it matters
This study outlines the specific endocrine costs of extreme contest leanness—notably suppressing the IGF-1 and androgen axes alongside muscle strength—while demonstrating that these multi-system perturbations are fully reversible with prolonged post-competition energy restoration.
Limits
The sample size is relatively small (10–13 athletes per subgroup), and allocation to competing versus control groups was non-random. The abstract reports p-values only, omitting effect sizes, means, and confidence intervals. Female-specific sex hormone findings (such as changes in estradiol or FSH) are not detailed in the abstract.
Cited by
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